Deletion of Glu139 in β-tropomyosin caused by a point mutation in TPM2 gene is associated with cap myopathy characterized by high myofilament Ca<sup>2+</sup>-sensitivity and muscle weakness.
The distal arthrogryposis syndromes associated with TPM2 mutations include the less severe forms, with congenital contractures mainly of the hands and feet and mild or no muscle weakness.
Hence, we recorded and analyzed the X-ray diffraction patterns of human membrane-permeabilized muscle cells expressing a particular beta-tropomyosin mutation (R133W) associated with a loss in cell force production, in vivo muscle weakness, and distal arthrogryposis.
A novel E41Kbeta-tropomyosin (beta-Tm) mutation, associated with congenital myopathy and muscle weakness, was recently identified in a woman and her daughter.
A novel R133Wbeta-tropomyosin (beta-Tm) mutation, associated with muscle weakness and distal limb deformities, has recently been identified in a woman and her daughter.
Here we report a deletion in the beta-tropomyosin (TPM2) gene causing cap disease in a 36-year-old male patient with congenital muscle weakness, myopathic facies and respiratory insufficiency.
We describe two patients, a woman and her daughter, with muscle weakness and distal arthrogryposis (DA) type 2B, caused by a heterozygous missense mutation, R133W, in TPM2, the gene encoding beta-TM.